1. Field of the Invention
The present invention relates to a printing apparatus which prints an image on a sheet by ejecting ink.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2009-196208 discloses an ink-jet printer in which ink is first supplied from an ink cartridge to a downstream tank and which has an ink circulation path for circulating ink between an ink head, an upstream tank, and a downstream tank.
However, according to Japanese Patent Laid-Open No. 2009-196208, one pump is used to circulate ink. Thus, under some conditions for ejecting ink from the ink head, the amounts of ink reserved in the upstream tank and downstream tank are not stable. This causes a problem that simultaneous implementation of a continuous printing operation and ink circulation is difficult.